Red tide is a world-wide phenomenon and is the sudden appearance of marine organisms that produce discolored water and various problems. In Florida the red tide organism Gymodinium breve is associated with mass marine fatalities, with economic costs estimated at $20 million (for a three-month outbreak) and with environmental health hazards. These include respiratory problems and skin irritation that effect thousands near the beaches that are often littered with millions of dead fish. A material ("aponin"), isolated from red tide water, is cytolytic toward G. breve and it is proposed to extend the knowledge about aponin properties to potential management of red tide environmental health hazards. The environmental degradation of aponin would be investigated by measuring the effect of natural salinity, pH, temperature and bacteria on aponin cytolytic activity. Air borne particles from lysed G. breve cells seem to be responsible for respiratory problems and the effects of aponin on the volatility would be investigated. It appears that aponin causes these particles to agglomerate, to reduce the ichthyotoxicity, and hopefully, the volatility as well. Management techniques of applying aponin would be investigated on larger scale to determine the effect of aponin on vertically migrating G. breve cells using a model ocean system. Large-scale production of aponin would be investigated, the characterization of aponin would be continued. The activity of aponin toward other marine organism and toward other red tide organisms is part of the long term study aimed at reducing health hazards of red tide outbreaks.